1. Field of the Invention
The present invention relates to locking pins and, more particularly, to a twist pin for use in combination with a fluid coupling.
2. Description of the Prior Art
Various forms of locking pins have been developed for providing locking engagement between two or more parts. These fasteners include roll pins, cotter keys, head pin fasteners, hairpin fasteners, clinch pins, hitch pins and similar clips.
One particular application of typical prior art fasteners is in combination with fluid couplings 2 wherein an inner tubular member 3 is received within an outer sleeve 4 as illustrated in FIG. 1. The inner tubular member 3 and outer sleeve 4 have coaxially aligned apertures 5a and 5b for receiving a fastener 6 which secures the relative positioning of the inner tubular member 3 and outer sleeve 4. A typical fastener 6 used for such an application is a U-shaped retaining clip having a straight portion 7 and a crimped portion 8. The straight portion 7 passes through the coaxially aligned apertures 5a and 5b while the crimped portion 8 engages the outside surface of the outer sleeve 4 thereby locking the pin 6 in place.
A problem associated with traditional retaining clips 6 is that they are often difficult to install within and remove from the fluid coupling 2. As may be appreciated, upon installation and removal the crimp portion 8 must be forced outwardly by the outer sleeve 4 such that a bend may selectively lock and unlock the outer sleeve 4 and inner tubular member 3 in position. The installation and removal of conventional retaining clips 6 therefore often requires the use of special tools.
One common fluid coupling application utilizing fasteners provides for a spray head 9 of the type used in the cleaning industry supported by the outer sleeve 4. More particularly, the spray head 9 and fluid coupling 2 are passed through a ferrule for insertion into a processing vessel. Once positioned within the vessel, the spray head 9 is utilized to clean the interior thereof.
Standard prior art retaining clips 6 have a straight portion 7 which is often too long to pass through the inner diameter of the ferrule. As such, the straight portion 7 of the retaining clips 6 are often shortened such that the straight portion 7 does not extend much beyond the outer sleeve 4. While this permits the fluid coupling 2 to pass through the ferrule, a new problem results as the shortened retaining clip 6 is often difficult to properly position in locking engagement with the outer sleeve 4. More particularly, the crimped portion 8 of the shortened retaining clip 6 often inhibits coaxial alignment of the straight portion 7 within the apertures 5a and 5b in the outer sleeve 4 and inner tubular member 3. As such, assembly of the fluid coupling 2 is often a very difficult process.
Accordingly, there is a need for a locking pin which may be simply inserted and removed between cooperating parts for selectively providing a positive lock between such parts. Further, there is a need for such a pin having a compact shape thereby requiring a minimum amount of space.